In which of these figures will the diagonals not always be perpendicular?

Triangle abc and triangle deg are similar right triangles. which proportion can be used to show that the slope of ac is equal to the slope of dg? a) 4 − (−7) / 0 − 4 = −1 − 10 / 4 − 8b) −4 − (−7) / 0 − 4= 4 − 8 / −1 − (−10)c) 0 − 4 / −4 − (−7) = −1 − (−10) / −4 − 8d) 0 − 4 / −4 − (−7) = −4 − 8 / −1 − (−10)